The present invention relates to the general technical field of devices for closing a cover on a container in order to form a vessel for cooking, preferably under pressure.
The present invention relates more specifically to a locking-unlocking device for locking a cover on a container in order to form such cooking vessel, the locking-unlocking device being composed of locking jaws movably mounted on, and spaced apart around the circumference of, the container, the jaws being capable of being subjected to the action of an unlocking means in order to move them away from their position for locking the cover on the container.
Locking-unlocking devices for vessels for cooking under pressure are already known in the art. For example, German Patent Application DE-A-4026166 discloses a device having jaws mounted in a cover to be radially movable. The jaws, of which there are two, are disposed diametrically opposite one another in the body of the cover and are intended to grip the peripheral edge of the container in their closing position. Displacement of the jaws is controlled by a control device actuated by a button, the control device being mounted at the center of the cover to be movable along the vertical axis of symmetry of the vessel. The control device is provided with specially formed engagement surfaces which act, upon displacement of the control button, on inclined surfaces which are fixed to the jaws in order to displace them radially. Such a control system thus transforms an axial movement into a radial displacement movement of the jaws between opening and closing position.
Such a system eliminates the necessity for establishing a relatively precise position between the cover and the container at the start of closing. On the other hand, such a system requires the operation of a series of parts which are movable relative to one another in order to assure control and displacement of the jaws. Considering the overall arrangement, the operating cost and the relative operating reliability of the prior art arrangement, it does not represent an optimal arrangement.
In addition, it must also be noted that the centered position of the control button can be considered as a factor which has a negative influence on the overall safety of appliances constructed according to the above-described prior art principle, to the extent that the user can be tempted to utilize the button as a means for gripping, and possibly even carrying, the vessel. In such a case, the user risks inadvertently activating the device for opening the jaws.
Finally, it is in order to note that the above-described control mechanism implies that the user must exert a substantially bidirectional control force.